1. Field of the Invention
This invention generally relates to X-ray apparatus having an X-ray tube and a film cassette tray for taking exposures in X-ray diagnosis. More particularly, this invention relates to an X-ray apparatus which is equipped for taking exposures in vertical and horizontal directions.
2. Description of the Prior Art
In the brochure "Ceiling Support 3D/3D-M for Attachment of X-ray Tube Assemblies and Image Intensifiers," published by Siemens Aktiengesellschaft, West Germany, is disclosed a ceiling support device which is designed as a carrier for an X-ray tube assembly and an image intensifier. This support device especially allows utilization of the X-ray tube assembly and the image intensifier in X-ray diagnosis. The ceiling support device is independent of any floor support. One of the main parts of the support device is a telescopic column or crane extending in a vertical direction from the ceiling. The telescopic column may be movable in longitudinal and transverse ceiling tracks. It may also be fixed to the ceiling so that only vertical movements are possible. For instance, the ceiling support device may be applied in connection with a bucky table. In one version of the known ceiling support (see FIG. 3 of the brochure "Ceiling Support 3D/3D-M," supra) a horizontally extending mounting arm is attached to the lower end of the column. The X-ray tube assembly which comprises an X-ray tube and a collimator is attached to one end of this mounting arm. Attached to the other end of the mounting arm is a control box. This box contains control switches, an angle indicator allowing oblique angles to be easily set and reproduced, a light beam indicator permitting exact alignment of a control beam with the center of a cassette tray located in the bucky table, and a tape measure showing the focus/film distance for radiographs using horizontal or oblique beam projections. Radiographs with vertical beam projection are also possible. The switches in the control box are lock releases for horizontal and vertical movements, a latch release for rotational movements, and a lock release for oblique settings.
The known ceiling support allows for X-ray exposures of a patient in a vertical and a horizontal direction. As already mentioned, a first film cassette tray is positioned in the table top beneath the patient. In another version the X-ray tube is located beneath the patient and the film cassette above the patient. This also allows for horizontal exposures, when the second film tray is used which is located in the bucky wall stand. It will be noted that the two trays are not operationally connected to each other.
In order to move the X-ray tube from a position where radiation is emitted in a vertical direction to a position where radiation is emitted in a horizontal direction, the X-ray tube assembly must be rotated about the longitudinal axis of the mounting arm. A cassette tray for horizontal exposures is provided in the separate lucky wall stand (see FIG. 4 of the brochure "Ceiling Support 3D/3D-M" supra). Such a tray is not provided on the column or on the mounting arm. In other words: the known ceiling support takes exposures in a vertical direction of radiation using the film cassette tray which is built into the bucky table. For horizontal exposures, the additional wall stand having built-in a second film cassette is required. Therefore, an apparatus equipped for horizontal and vertical exposures becomes expensive. In addition, switching from the vertical to horizontal radiation and exposure position is time consuming, since adjustment work is needed to position the second cassette in a vertical position in front of the X-ray tube assembly. Whenever this position is taken, the focus-film-distance has to be measured to determine the correct exposure time. Since the second film tray is arranged in a wallstand, access to the patient is limited especially when lateral exposures are to be taken.
In German Offenlegungsschrift or published application No. 21 41 461 is disclosed an X-ray apparatus containing a ceiling support device or column, an X-ray tube and a film cassette. To the lower end of the column is connected a transverse arm which pivots about an axis that is arranged perpendicularly to the longitudinal axis of the column. To one end of this transverse arm is pivotly connected a first support arm, to the free end of which is pivotally attached the X-ray tube. To the other end of the transverse arm is pivotally connected a second support arm to the free end of which is pivotally connected the film cassette. The pivoting axes of the first and second arms are parallel to the pivoting axis of the transverse arm. There is provided a driving mechanism by which, independently from the rotational position of the transverse arm, the orientation of the first support arm is maintained and by which the central beam of the X-ray beam is permanently kept parallel to the longitudinal axis of the arm. This X-ray apparatus is useful for many applications. However, due to its sophisticated driving mechanism, its production is too expensive for applications where X-ray exposures only in a horizontal and a vertical direction have to be taken. In addition, free access to the patient is limited, and problems may arise when a X-ray film tray is to be used instead of the X-ray image intensifier.
Frequently examinations are made of a patient's internal organs as for instance the stomach. In these examinations it is of interest to the physician to observe for example the action of a barium surry from the stomach wall of a patient resting on a stretcher or medical examination table. In these examinations, X-rays are taken laterally, that is transversely to the longitudinal axis of the resting patient. When the patient lies on his or her side, such exposure are taken in the direction from the front to the back, or vice versa, and when the patient lies on his or her back or stomach, such exposures are taken in the direction from the left side to the right side, or vice versa. This means that the cone of X-rays leaves the X-ray tube approximately horizontally and is received by an X-ray film which is positioned approximately vertically. It is desirable to have an X-ray apparatus which can be used for these examination, using horizontal irradiation, but which can easily be changed over such that conventional examinations using vertical irradiation can be performed.